Distance acceptable several meters through walls is sufficient unless we want to turn only several tens of meters! but why? Fountain, outdoor lighting? I confess I have not tested the maximum distance in any case within all the parts it even works the floor and the basement with Module From the Ground Floor. Easy connection. To replace an existing switch shunt the 2 son of former switch. Place new on the box. Put the relay module in the box lighting. Press and it lights up. It's beautiful technology I will recommend several.